JPS59208246A - Oil seal device for lubricating track chain joint - Google Patents

Abstract

In an oil seal for lubricated track chain joints, particularly for track-type vehicles, of the type with a flanged primary ring of a flexible material and a secondary ring of a resilient material, the annular portion (6) of the flanged primary ring (5) carries a metal ring (7) embedded in it.

Description

DETAILED DESCRIPTION OF THE INVENTION a) Industrial Field of Application The present invention relates to an oil sealing device for a lubricated track chain joint for a track vehicle. The first joint is a screw fixed to the link.

The oil sealing device is designed to seal between the wall of the seat provided in the link and the front wall of the bushing.

The invention particularly relates to an oil sealing device of the type mentioned above, which oil sealing device comprises an annular flange member, referred to as the first ring, which is sealed by nine lips projecting 1' from the flange to the front face of the bushing. and a second lip to maintain the lip pressed against the bush and to ensure a seal between the first ring and the sealing wall receiving the seat.
It consists of an elastic annular member called a ring.

b) In order to ensure effective sealing in conventional technology lubricated orbital chain joints, it is essential that several key conditions be maintained.

1 Continuity of contact between the sealing lip (first ring) and the front surface of the bush head.

2. Uniformity of contact pressure along the entire circumference of the sealing surface.

3. Contact pressure values within precise maximum and minimum limits, depending on various structural and operating conditions, to ensure the sealing ability and maintenance of this ability over the expected lifetime (in operating hours) of the joint. Maintain.

In particular, it must be taken into account that, over the course of the working time, wear occurs primarily on the front contact surface of the bushing head, which is gradually formed and grooved by the creeping of the fingers. In addition, this groove eliminates radial play between the pin and bushing with misalignment (parallel and oblique) occurring between the respective axes, as well as wear due to construction and assembly tolerances and subsequent steps. For various reasons, such as the imperfect orthogonality of the front molding surface on the bushing in relation to the axis of the joint, it is not located exactly along the circumference with a constant radius, and Also for other reasons coupled with the operating characteristics (discrete loads, recoil, vibrations, etc.), the actual contact between the bushing surface and the fingers varies up to a minimum radius with simultaneous changes in the contact pressure.

Therefore, the worn area on the bushing is actually annular (variably and irregularly hollowed out) and not just a line. This phenomenon occurs in a very roundabout way and increases gradually from the beginning of the joint operation.

Based on these considerations, the metal (or anyhow hard material) that would tend to creep on the bushing head.
It is clear that surface-based sealing must be taken into account.

Practically all devices based on metal front seals have been found to be unsuitable for this purpose. This can be achieved by appropriate selection of materials with elastomeric properties (
A substantially flexible and pliable contact strip should be provided to match the deterioration of the bushing head) and to ensure an effective seal over the foreseen service life of the fitting. Forward finger seals with appropriate inherent anti-wear capabilities have been used to enable positioning.

These devices can be classified into two basic types: A, a substantially flexible first ring, and B, a substantially rigid first lineage.

In devices of type B mentioned above, there is always a rigid member (of metal or plastics material) which supports a part made of an elastomer of the polyurethane type and which is adapted to have a sealing effect and which is subjected to various methods. are firmly connected. However, the rigid member is always arranged at the rear of the sealing lip, and the thrust generated by the second ring (consisting of suitable rubber) is always transmitted indirectly to the sealing lip via the rigid support. . This is especially true with respect to the fundamental characteristics mentioned above (uniformity of the contact pressure distribution between the sealing lip and the front face of the bushing along the entire contact line), and the operation of these Provides operating conditions for the device. in fact,
There is no possibility of elastically deforming the absolutely unyielding first ring, and only the moderate elasticity of the polyurethane thickness forming the sealing ring which compensates for the irregularities of the front face of the bushing can be exploited.

Flexible first ring devices were developed because it is not possible to practically guarantee the uniformity of the contact pressure along the sealing zone exhibited by a rigid type of first ring. However, in these devices, the flexibility and insufficient stiffness of the first ring impose limitations on the radial loads that are essential to guarantee the sealing action in the seat receiving the C sealing device. . This flexibility results in a very strong deformation of the first ring that negatively affects the exact geometrical plane and positioning of the sealing lip (which must be taken into account) It is essential to ensure a lubricating film in the contact areas between the fingers under all conditions or the fingers will be destroyed immediately). Attempts have been made to eliminate the above-mentioned drawbacks by placing the sealing device under deformation on a member (different from the sealing device) which acts as a rigid support while limiting the deformation. This element is a spacer already present in the joint with the action of an axial thrust bearing and a limiter of the axial compression that can be generated on the sealing device. However, in various applications where a spacer is not present or where the spacer is improperly shaped or unsuitable for the purpose, these devices required to be mounted on this outer member may not be properly or independently unable to operate.

C) Problems that the invention seeks to solve The purpose of the invention is to preserve the advantages of the two types (rigid first ring or flexible first ring) and at the expense of the disadvantages inherent in both types. The object of the present invention is to provide an oil sealing device that eliminates oil.

d) Means for solving the problem This objective is achieved by the use of a first ring with a mixed action (half stiff with respect to the parts encountering radial loads, while eliminating the associated deformations, and suitable semi-flexible with respect to the part providing a good sealing effect, i.e. the front flange with a sealing lip).

In other words, the oil sealing device according to the invention is of the type having a first flanged ring of flexible material and a second ring of elastic material, with the annular portion of the first flanged ring being attached to it. It is characterized by supporting an embedded metal ring.

e) Examples An example of an oil sealing device according to the present invention shown in the accompanying drawings will be described below.

In the figure, reference numeral 1 indicates a joint pin fixed to link 2 of the chain, and reference numeral 3 indicates a bushing fixed to another not-illustrated link of the chain. Code 4 is pin 1
A spacer is shown for limiting relative axial movement between the bushing 3 and the bushing 3.

The first flanged ring 5 supports a metal ring 7 embedded in the annular part 6 and has a sealing lip 8 projecting from the annular part 6. The reference numeral 1° indicates the elastic second ring.

With this configuration, the axial thrust generated by the second ring (generally made of nitrile rubber) 10 is transferred to the first ring 5.
The front 7 of the flange 9 is distributed on the rear face of the flange 9, which retains a very large flexibility directly, rather than through a somewhat rigid member.

In this method, the actual contact pressure (i.e. the axial thrust of the fingers 8) is based on the local compressive action of point contact by the flexible flange 9 on the corresponding surface of the second rubber ring 10, and therefore at one point. Exists at one point. It is not the average thrust generated by the rubber ring 10 on a non-deformable rigid support that must distribute the thrust sequentially onto the flange of the first ring. The advantage of a flexible first ring in relation to a ring of hard material is that, due to the deterioration of the front face of the bushing where the sealing action must be generated, the local contact pressure is essential for the sealing action. The risk of falling below a minimum value of On the contrary, it can easily occur.

- Due to the presence of the metal ring 7 embedded in the annular part 6 of the first flanged ring 5, the device according to the invention has the advantage of being self-sufficient in terms of radial loads, with no accompanying deformations. It also has the advantage of not being In theory, the device according to the invention can also be used in the case of other devices that are not self-sufficient.

Within the limits of the particular application, consideration must be given to the significance and influence of the seat and space machining tolerances to be accommodated on the axial thrust and radial compression values encountered in the seal of the present invention. .

For the various devices under consideration, given the axial deformation (
Assuming that the spacer heights are equal, a difference of a few tenths of the seat diameter (i.e., the machining tolerance of the seat) will result in some change in the value of the axial thrust generated by the device. discovered experimentally.

The generated axis when the effect of tolerances on the outer diameter of the spacer is applied to a variable unavoidable component (when the effect of the spacer is to support the first ring of the flexible type) Another reason for the variability of the directional thrust is added, increasing the overall difference between its maximum and minimum values.

Since a minimum thrust value must be guaranteed for the effectiveness of the sealing action, the resulting maximum value is increased by increasing the contact pressure. This causes accelerated wear of the sealing members, both the metal part (brush knob head) and the polyurethane fingers. By taking into account that the machining tolerances (for the outer diameter) of the spacing +J amount to a few tenths of a print, the effect of the component aperture is therefore not at all insignificant and meaningless.

Therefore, by embedding the reinforcing member 7 in the filter oil sealing device in the C1 elastic member, the remaining diameter of the first rick 5 is not affected by its tolerance. The therapeutic benefits of pressure are clear.

This diameter is therefore easily maintained within precise tolerances at a greatly reduced cost of just tie dimensions, thus eliminating the effect of spacer diameter variability on the axial thrust generated by the device. do.

Furthermore, in connection with the present device having a flexible first ring, the direction of the torque transmitted between the first ring and the second ring must be considered. A cree big occurs between the first ring and the second ring.
It is essential that no relative rotation occurs with the ring or of the entire device within the receiving seat.

Therefore, the connection between the receiving seat and the device and the connection between the two rings forming the device is forced to be integral with the seat as a whole instead of the device in order to prevent said rotation, and It is essential that the lock be sufficiently locked to allow creeping contact between the fingers and the front face of the bushing. Consequently, for practical reasons, when the device is compressed, interference with the diameter of the seat is not advisable, and said interference is only caused by compression of the device until it reaches its effective diameter. It is advisable that a constant density of radial loads is required for sealing purposes and also for transmitting resistance couples. Moreover, in this respect, a device with a sufficiently flexible first ring is less optimal, has poorer resistance capacity and is more deformable.

Utilizing the robustness of the axial position of the first ring according to the invention provides sufficient support for substantially radial loads and, in addition, if necessary for x1 radial compressive action.
A set of indentations can be provided in the trailing edge area of the first ring that engage the second rubber 9 ring at 1 and 2) and increase the resistance of the device to torsional stresses.

f) Effects As mentioned above, the oil sealing device according to the present invention supports radial loads due to the presence of the reinforcement, and seals by point contact without the mediating action of hard members. It transmits the axial thrust generated by the second rubber ring directly to the lip, thus satisfying the above basic conditions and, in addition, providing significant features for Iw'I;;n stress and reduced overall deformation. resistant and also of flexible type, chosen primarily for its anti-wear properties.
It says "Otsu to gate" and "Otsu to 1" which uses lrl uritan.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of an oil sealing device applied to a joint of a lubricated track chain for a track-type vehicle. In the figure, numeral 5 is a first ring, 6 is an annular portion, 7 is a metal ring, and 10 is a second ring.

Claims (1)

[Claims] In an oil sealing device for a lubricated track chain knitting device for a track-type vehicle having a first flanged relay made of a flexible material and a second ring made of an elastic material, the annular portion of the first flanged ring is Buried in the annular part
An oil sealing device for a lubricated orbit F/ENO joint characterized by supporting a two-metal ring.